1. Technical Field of the Invention
The present invention relates to topical compositions for the treatment or prevention of keratinization disorders, to processes for the preparation of such compositions and to their formulation as cosmetic or pharmaceutical products. These compositions are useful, in particular, for the treatment of acne.
2. Description of Background and/or Related and/or Prior Art
Acne is a common multifactor pathology which affects skin rich in sebaceous glands (face, scapular region, arms and intertriginous regions). It is the commonest form of dermatoses. The following five pathogenic factors play a determining role in the formation of acne:
1. genetic predisposition;
2. overproduction of sebum (seborrhea);
3. androgens;
4. follicular keratinization disorders (comedogenesis); and
5. bacterial colonization and inflammatory factors.
Several forms of acne exist, all having in common that the pilosebaceous follicles are attacked. In particular, exemplary are acne conglobata, acne keloid on the back of the neck, acne medicamentosa, recurrent acne miliaria, acne necrotica, acne neonatorum, premenstrual acne, occupational acne, acne rosacea, senile acne, solar acne and acne vulgaris.
Acne vulgaris, also known as polymorphous juvenile acne, is the commonest. It comprises four stages:
Stage 1 corresponds to comedonal acne, characterized by a large number of open and/or closed comedones and of microcysts.
Stage 2, or papulopustular acne, is of mild to moderate seriousness. It is characterized by the presence of open and/or closed comedones and of microcysts but also of red papules and of pustules. It mainly affects the face and leaves few scars.
Stage 3, or papulocomedonal acne, is more serious and extends to the back, to the thorax and to the shoulders. It is accompanied by a larger number of scars.
Stage 4, or nodulocystic acne, is accompanied by numerous scars. It exhibits nodules and also large painful purplish pustules.
The various forms of acne described above can be treated with active principles, such as anti-seborrhoeics and anti-infectives, for example benzoyl peroxide (in particular the product Eclaran® marketed by Pierre Fabre), with retinoids, such as tretinoin (in particular the product Retacnyl® marketed by Galderma) or isotretinoin (product Roaccutane® marketed by Laboratoires Roche), or with naphthoic acid derivatives. Naphthoic acid derivatives, such as, in particular, 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid, commonly known as adapalene (the product Differin® marketed by Galderma), are widely described and recognized as active principles which are as effective as tretinoin in the treatment of acne.